siteval

In the Preliminary Site Assessment, an initial field survey is conducted of the site,
the existing system, and potential leachfield locations. During this inspection, focus is
directed toward identifying slopes, soil series, and issues of setback concerns. Often,
shallow soil samples are obtained through the use of a 2" AMS hand augur in order to help
identify shallow soil regimes in the potential leachfield.

There are several distinct phases that must be accomplished in order to specify the
proper septic system for its optimal use.

In the Site Assessment, a backhoe is utilized in order to more accurately identify
subsurface conditions, shallow groundwater, shallow aquitards (e.g., rock and clay
substrata), and optimal depths for the leaching system. Often, the local health inspector is
invited to witness a portion of this phase.

Once the soil regimes (and its limitations) are identified in this phase, typically,
the type of leaching system is selected. There are many leachfield alternatives which can
be utilized to compensate for varying site and soil constraints. They all include variations of
above ground and below ground systems. Above ground systems include sand-filled and
at-grade mound systems. Below ground leaching systems include the standard leachfield,
pressure distributions systems, fill systems, shallow in grade systems, and, occasionally,
drip irrigation.

Next, the projected wastewater flow is calculated. Such values can be derived on
the basis of current water use, sophisticated tables, County Health Department standards,
similar projects elsewhere, and projected number of users.

In many jurisdictions, the depth of shallow groundwater during the wet weather
season must be monitored. This effort is initiated by the placement of shallow wells (<8')
around the perimeter of potential leachfield sites through the use of either a backhoe or drill
rig. These wells are then monitored from once to several times during the wet weather
period in order to ascertain the steady state groundwater depths. This information is then
used to select the leachfield location, the type of leaching system, and is frequently used in
the mounding and nitrate cumulative impact report.

Once the optimal leachfield locations have been selected, the permeability of the
substrata is obtained through the Percolation Test. This information is essential in order to
adequately size the leachfield for the projected flow estimate. Typically, these tests are
performed for a period from four to six hours.

Depending on the jurisdiction and the size of the project, a Cumulative Impact Study
is often required. Typically, this report models wastewater mounding and nitrate additions to
the shallow groundwater. The mounding study models the depth of the groundwater during
steady state, wet weather conditions combined with the wastewater flow from various
leachfield designs and configurations.

In the final phase, Plans and Specifications are prepared for the complete system
which include both the treatment and leaching systems. There are a number of treatment
system alternatives available, each dependent on soil limitations and the type of leachfield
system specified. Treatment systems include the septic tank, effluent filter, intermittent
sand filter, recirculating filter, and aerobic treatment systems.